1. Field of the Invention
This invention relates to optical data storage systems, and more particularly to such systems which have removable optical media.
2. Description of the Prior Art
Optical data storage systems such as disk drives use laser beams to record and read data from optical data storage disks. The disks are typically packaged in a cartridge for easy removal from the drive. A problem with these systems is that dust and other particles can collect inside the drive and adhere to the optical elements such as the disk or the objective lens which is used to focus light to the disk. The collection of dust and particles causes a degradation in the signal to noise ratio and can ultimately cause the disk drive to fail.
Various schemes have been proposed to try and solve the contamination problem. The optical disk cartridges have been equipped with shutters to prevent contamination of the disk. See Japanese published applications JP 02-304767, published Dec. 18, 1990, by Horie, et al.; and JP 02-187958, published Jul. 24, 1990, by Kishi, et al. Some drives use filters or particle traps. See Japanese published applications JP 61-239482, published Oct. 24, 1986, by Yabuuchi, et al.; JP 02-276056, published Nov. 9, 1990 by Nakano, et al.; JP 02-58789, published Feb. 27, 1990, by Fujino, et al.; JP 01-185840, published Jul. 25, 1989, by Kimura, et al.; JP 63-124282, published May 27, 1988, by Sasaki, et al.; JP 02-14483, published Jan. 18, 1990, by Osumi, et al.; and IBM Technical Disclosure Bulletin, Vol. 33, No. 10B, March 1991, pp. 484, by Yanker. There are also drives which contain lens cleaners. See Japanese published applications JP 01-287893, published Nov. 20, 1989, by Warisaya, et al.; JP 02-105340, published Apr. 17, 1990, by Sugano, et al.; JP 02-31339, published Feb. 1, 1990, by Miyajima, et al.; JP 62-40641, published Feb. 21, 1987, by Kitazawa, et al.; and JP 02-152028, published Jun. 12, 1990, by Suzuki, et al. PCT application W09006576, published Jun. 14, 1990 by Hake shows the use of a lens cover. U.S. Pat. No. 4,814,906, issued Mar. 21, 1989 to Suzuki, et al.; and Japanese published application JP 63-269392, published Nov. 7, 1988 by Ouguchi, et al. show examples of contamination protection schemes for magnetic disk drives.
What is needed is an optical disk drive system with removable media which inexpensively, compactly, and efficiently solves the particle contamination problem without sacrificing the interior airflow necessary for proper cooling.